This invention relates to a sheet separating device for separating flexible disc-shaped sheet materials such as floppy discs one by one from a stack of such sheet materials which have holes formed therein.
In a process for producing flexible disc-shaped sheet materials each having a hole formed therein, a stack of such sheet materials are sometimes fed to a subsequent next step.
In such a case, the flexible disc-shaped sheet materials are often contacted so closely with one another that they cannot be separated easily from one another. Accordingly, when the sheet materials are to be fed to a next step, air is blown from an air nozzle 1 to an upper side portion of a stack 3 of sheet materials 2 as shown in FIG. 7a to float an uppermost one and some underlying ones of the sheet materials to provisionally separate them, and then a vacuum pad 4 is operated to attract and draw up an end portion of the uppermost sheet material 2. In order to improve the separating efficiency, a rotary vacuum pad 5 as shown in FIG. 7b may otherwise be used.
However, in such separating devices as described above, an air-blown position is apt to be displaced since stacks 3 of sheet materials 2 are fed one after another to a position or height of the air nozzle 1 each time a sheet material 2 is to be separated. If such displacement occurs, a plurality of sheet materials 2 may be floated or otherwise sheet materials 2 cannot be floated sufficiently. In case sheet materials 2 are not floated sufficiently, the vacuum pad 4 which has no separating function cannot draw up nor separate the sheet materials 2. Even with the rotary vacuum pad 5 which has a separating function, where sheet materials 2 are not floated sufficiently, there is some limitation to separation of the sheet materials 2 from other sheet materials 2 below by making use of an elastic reactive force of end portions of the sheet materials 2, and if the contacting force is superior to the elastic force, the sheet materials 2 cannot be separated.
Thus, the conventional sheet separating devices have a defect that a separating operation cannot be assured because they employ an unstable air blowing system and a sheet material is attracted at an end portion thereof which presents a low elastic reactive force. Accordingly, a plurality of sheet materials may be fed sometimes and no sheet materials may be fed at other times, resulting in possible occurrence of stopping of a machine for a subsequent next step due to possible troubles caused thereby.